Hi folks
Firstly, apologies I couldn't make today's call. I've spent my RDF'ing
time this week talking to a lot of people about schema.org,
rdfa/microdata etc.
I want to bring something up related to that: back in RDFCore WG we
called it "long range" data-typing, but didn't figure out a way to
make it work. I'd appreciate if someone could articulate the
connection to current discussion on literals, and suggest if there are
ways we could make it work in 2011.
The idea is that many properties are deployed as if their values take
string form, but we know from the schema that the values can be
interpreted e.g. as integers or dates.
RDF's datatyping mechanism puts a lot of burden on instance data, and
in some contexts (eg. Website markup) this can be problematic. So for
example http://schema.org/docs/datamodel.html chooses Microdata over
RDFa and lists 'datatypes' as one of the complexity burdens of RDFa
markup.
In practice I don't think a lot of sites will enjoy marking up each
property value occurence with a datatype, ... and so vocabulary
designers are tending not to make datatyping explicit.
So for example in FOAF we have foaf:age, which Peter Mika originally asked for.
http://xmlns.com/foaf/0.1/#term_age "The age property is a
relationship between a Agent and an integer string representing their
age in years. "
This can be used in RDFa as so: <p>blah blah <span
property="foaf:age">39</span> blah</p>.
If we try to persuade publishers to put datatype="xsd:integer"
alongside each age, ... we'll have a hard time. So is there anything
we can do at the schema level? Mumble mumble range mumble...
Pat - can you remember why we couldn't make this work in the semantics
last time?
cheers,
Dan
(another possibility is to do something in RDFa's profile mechanism,
http://www.w3.org/TR/rdfa-core/#s_profiles )